Metallic liner system

ABSTRACT

A liner system for retaining liquid in a storage tank. The liner system includes a continuous metallic liner which has sides which are substantially coextensive with the sidewalls of the tank and a bottom which is substantially coextensive with the floor of the tank. Upright expansion joints, provided in the sides of the liner, compensate for expansion and contraction of the sides in a circumferential direction and expansion joints, provided in the bottom of the liner, compensate for expansion and contraction in the bottom of the liner. Hanger members are secured to the upper portion of the tank and are resiliently mounted thereto. The upper end of the sides of the liner engage the resiliently mounted hangers so as to compensate for expansion and contraction of the liner in a vertical direction.

United States Patent H O N 2m0 232 2 20 2 2 2 2 man a a ma a s e e Or. 0US 60 db m amw SEJSD 34899 66666 99999 HHHH W0035 11 2687 0 5 3 94860Primary Examiner-Raphael H. Schwartz Attorney Molinare, Aligretti;Newitt & Witcoff ABSTRACT: A liner system for retaining liquid in astorage tank. The liner system includes a continuous metallic linerwhich has sides which are substantially coextensive with the sidewallsof the tank and a bottom which is substantially coex- 2 tensive with thefloor of the tank. Upright expansion joints, 220/1 provided in the sidesof the liner, compensate for expansion 3656 /14 and contraction of thesides in a circumferential direction and expansion joints, provided inthe bottom of the liner, compen- A, l5 sate for expansion andcontraction in the bottom of the liner. Hanger members are secured tothe upper portion of the tank and are resiliently mounted thereto. Theupper end of the sides of the liner engage the resiliently mountedhangers so as 220/63 to compensate for expansion and contraction of theliner in a 220/9-A1 vertical direction.

References Cited UNITED STATES PATENTS 2,260,393 10/1941McCarthy...............

[22] Filed Dec. 4, I968 [45] Patented Jan. 26, 1971 [73] AssigneeInstitute of Gas Technology a non-profit corporation of Illinois [54]METALLIC LINER SYSTEM 10 Claims, 10 Drawing Figs.

[52] US. Field of 3,085,708 4/1963 Dosker.........................

PATENTED M26197: 3558.000

SHEET 1 [IF 3 PATENTEU JAHZS l9?! SHEET 2 OF 3 ZZZIIIIIIIIIIIIIIIIIIIIIIIIII|I||I||||| .1

l I I Z l 4 000 M ---IIWIUFII-iiiU IIIIII I I I I6- I I I HI I I I H vH/0 wmm I mm,

ll r l..

.1- 40 v l v II III M 1' lgg METALLIC LINER SYSTEM BACKGROUND OF THEINVENTION FIELD OF THE INVENTION AND DESCRIPTION OF THE PRIOR ART Thisinvention relates to a liner system for retaining liquid in a storagetank and it particularly relates to such a liner system which isparticularly useful in storing liquid gas at cryogenic temperatures.

Normally the only problem that is encountered with the storage ofliquids at atmospheric pressure is the prevention of the liquid fromescaping from the container in which it is stored, a large storage tank,for example. Problems of retaining liquid in a storage tank are normallygreater when storage is at superatmospheric pressures, but nevertheless,significant problems are encountered even when the liquid is stored atatmospheric pressure. Such problems include the selection of aconstruction material which will not permit the passage of the liquid byseepage. For example, storage tanks are often constructed of concreteand the inside of the tank must be treated so as to prevent any loss ofthe liquid from the tank. Such loss of liquid can be caused by thepermeability of the material from which the tank is constructed, bystresses imparted to the storage container or a liner material whichultimately will cause cracks or apertures to form, or by a combinationof these two factors.

Particularly difficult problems are encountered in the storage of largequantities of liquid gas stored at cryogenic temperatures and atatmospheric pressures. Because of the extremely cold cryogenic storagetemperatures which must be withstood by the storage tank material andbecause of the insulation which must be used in such tank structures,separate liners for the interior of the storage tanks are used in orderto prevent the loss of the stored liquid gas from the tank. In US. Pat.application Ser. No. 526,983, now US. Pat. No. 3,418,812, there is shownand described an insulating system for a storage tank for retainingliquid natural gas at cryogenic temperatures. In this particularinsulating system the insulation is of a porous, foamed material. Theinnermost surface of the material is formed of separate blocks ofinsulated foam which are joined together in close proximity. Because ofthe porosity of the material and because of the spaces between theindividual blocks, it is essential that a liner be used in the interiorsurface of the blocks to prevent the egress of the stored liquid fromthe cryogenic storage tank. A flexible liquid and gas barrier or lineris formed as an integral part of the insulating panels wherein suchliners may be a laminated material of MYLAR (polyethylene terephthalatefiber) having a backing of lightweight fiber cloth and aluminum foil.Although once installed, this material is quite satisfactory, great caremust be exercised during this installation of the laminate so as toprevent creasing of the material, which will ultimately form pinholestherein. Such small holes cannot be tolerated because it will causeleakage of the liquid gas from the tank.

Because of the discussed inherent problems with the plastic film-metalfilm-fibrous laminate, metal liners, such as aluminum foil, may be usedon the inside of a tank for retaining the liquid. Although the aluminumor metallic liners are not subject to the same difficulties encounteredwith the laminated type of liner, other ditficulties are encountered.The interior of the cryogenic tanks must be capable of withstandingtemperatures cycling between extreme cold and normal temperatures. Thus,means must be provided for compensating for expansion and contraction ofthe metal liner while it is within the storage tank. If any undue stressis set up in the material during use, cracks may develop and the liquidnatural gas can escape from within the liner. It is therefore necessaryto construct the metallic liner in such a manner that it will avoidstresses of expansion and contraction of the liner so as to avoid cracksforming. In prior metallic liner systems, the expansion joints have beenof complex and expensive design. For example, it has been necessary touse a complex threedimensional expansion joint at the intersectionsbetween the sides and floor.

SUMMARY OF THE INVENTION It is therefore an important object of thisinvention to provide an improved liner system for the inside of storagetanks for storing liquids wherein the liner system avoids problems ofprior art liner systems.

It is also an object of this invention to provide an improved linersystem for the interior of storage tanks used for storing liquid naturalgas at cryogenic temperatures wherein the liner is of a metal materialso as to provide durability and ease of construction, but at the sametime substantially avoids complex expansion joints normally requiredwith other metal liner systems.

It is another object of this invention to provide an improved linersystem for storing liquid natural gas at cryogenic temperatures whereinthe liner system compensates for vertical expansion and contraction bythe use of special hangers resiliently mounted to the upper portion ofthe storage tank.

It is yet another object of this invention to provide an im proved linersystem for storing liquid natural gas at cryogenic temperatures whereinexpansion joints are located in an upright position along the sides ofthe liner and in ringlike configuration in the bottom of the liner andthe upper end of the sides of the liner are resiliently mounted.

Further purposes and objects of this invention will appear as thespecification proceeds.

The foregoing objects are accomplished by providing a liner system whichcomprises a continuous liner having sides which are substantiallycoextensive with the sidewalls of the storage tank and having a bottomwhich is substantially coextensive with the floor of the storage tank,first upright expansion joint portions in the sides of the liner tocompensate for expansion and contraction of the sides, second expansionjoint portions in the bottom of the liner to compensate for expansionand contraction of the bottom, hanger members resiliently secured to theupper portion of the tank, and means secured to the upper end of thesides of the liner to engage the hanger members to compensate forvertical expansion and contraction, whereby the sides are suspended in aposition substantially coextensive with the sidewalls and the bottom ismaintained in a position substantially coextensive with the floor.

BRIEF DESCRIPTION OF THE DRAWINGS Particular embodiments of the presentinvention are illustrated in the accompanying drawings wherein;

FIG. 1 is a top plan cross-sectional view through a tank using ourimproved liner system;

FIG. 2 is a vertical cross-sectional view taken through a tankconstruction of the type shown in FIG. 1;

FIG. 3 is an enlarged fragmentary plan view showing the expansion jointsused in a liner system;

FIG. 4 is a cross-sectional view taken along the line 4-4 of FIG. 3showing a detailed view of the expansion joints of the liner;

FIG. 5 is a detailed cross-sectional view taken along the line 5-5 ofFIG. 4;

FIG. 6 is a fragmentary cross-sectional view taken along the line 6-6 ofFIG. 3;

FIG. 7 is an alternate embodiment of our liner system, when the tankstructure is located entirely below the ground;

FIG. 8 is an enlarged cross-sectional view taken along the line 8-8 ofFIG. 7;

FIG. 9 is an enlarged detailed view showing the construction of thehanger member used in the embodiment of FIG. 7; and

FIG. 10 is a fragmentary detailed view taken along the line 10-10 ofFIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The liner system for retainingliquids in a storage tank, which will be hereinafter described indetail, may be used in any type of tank used for the storage of liquids.The tank structure may be entirely above the ground, partially above theground and partially below the ground, or completely below the ground.The tank structure may store liquids at atmospheric conditions, atatmospheric pressure and cryogenic temperatures, etc. It is to beunderstood, however, that the greatest utility of the liner systemsdescribed hereinafter is in the storage of liquid gases at cryogenictemperatures because of the various expansion joints and resilienthangers used in our liner system to compensate for expansion andcontraction of the liner.

Liquid natural gas is commonly stored in large storage containers atsubstantially atmospheric pressures but at cryogenic temperatures. Thepurpose of the storage of liquid natural gas at these conditions is tostore the maximum quantity of gas in a minimum space so that on peakdemand days, such as during cold weather, sufficient gas is availablefor heating purposes. It is in such storage tanks that our liner systemfinds its greatest utility.

In the accompanying drawings, two preferred embodiments of our linersystem are illustrated. 1n the first embodiment, shown in FIGS. 1-6,hanger members, used for suspending the liner, project upwardly from theupper portion or top of the tank when the tank structure is eithercompletely above the ground or partially above the ground. In theembodiment of P168. 7-10, the tank structure is completely below theground so that the hanger members are located entirely within the tankand are suspended downwardly from the top or upper portion of the tank.Each of these embodiments will be described in detail below.

Referring to the embodiment of FIGS. l-6, the storage tank 10 is locatedpartially above the ground. In the description of this embodiment, aswell as in the description of FIGS. 7-10, the walls of the tanks will beshown as being of solid concrete construction. It is to be understood,however, that in the storage of liquid natural gas at cryogenictemperatures the walls will generally comprise an outer supportingconcrete section, an outer liner which acts as a water barrier, andmultiple layers of insulating material, such as foamed polyurethane (notshown). Specific examples of tanks having such construc tion are foundin U.S. Pat. application Ser. No. 526,983, new U.S. Pat. No. 3,418,812,U.S. Pat. application Ser. No. 527,158, now U.S. Pat. No. 3,407,606,U.S. Pat. application Ser. No. 702,293, filed Feb. 1, 1968, and U.S.Pat. application Ser. No. 702,471, filed Feb. 1,1968. Since the linersystem used for the retention of the liquid is the subject of thepresent invention, the tank structure 10 will only be described ingeneral terms.

The tank 10 includes upwardly extending outer walls 12, a roof 114, anda floor 16. The liner, generally 18, is supported inside the tank andretains the liquid in place within the tank 10 so as to prevent theegress thereof from the tank.

The liner 18 has a bottom 20 which is substantially coextensive with thefloor 16 of the tank 10 and also has upright sides 22 which aremaintained substantially coextensive with the walls 112 of the tank 10.The upper end of the sides 22 includes integral strap members 24 whichengage a resiliently mounted ringlike support member 26.

Because the liner 18 is designed particularly for use with tanks forstoring liquid natural gas at cryogenic temperatures, the liner 18 isconstructed to avoid stresses which may be caused by expansion andcontraction of the liner material, when the tank 10 is cycled betweencryogenic temperatures for storing the liquid gas and higher normaltemperatures when the tank 10 must be repaired or serviced. The liner 18is designed so as to compensate for expansion and contraction of itsbottom 20 and of its sides 22, both circumferentially and vertically.

In the preferred embodiment, the bottom 20 of the liner 18 is formed byintegrally joining planar sections, such as the central portion 28, witha plurality of expansion joints 30 and 32. The planar portions, such asthe central portion 28 are formed by integrally joining, as by welding,sheets of metal such as from rolls of aluminum or steel sheeting. Asshown in FIGS. 3 and 5, the expansion joints 30 are integrally joined,as by welding, to the planar portions of the bottom 20. The expansionjoints 30 generally comprise thermal expansion metal which has thegeneral configuration of corrugated sections. The corrugated expansionjoints 30 expand when the temperature in the tank is raised and contractwhen the temperature is lowered, so that regardless of the temperature,the bottom 20 of the liner 18 remains substantially coextensive at alltimes with the floor 16 of the tank 10 without undue stresses being setup in the liner bottom. Preferably, a multiplicity of expansion joints30 are provided in the bottom 20. The bottom expansion joints arepreferably ringlike and substantially concentric with each other such asshown in FIG. 1.

The sides 22 of the liner 18 are maintained in close proximi ty to thewalls 12 of the tank 10 and generally comprise a plurality ofsubstantially planar upright sections 32 which are spaced apart by aplurality of upright expansion joints 34. The expansion joints 34 extendfrom the upper edge of the liner sides 22 downwardly to the intersectionbetween the bottom 20 and the sides 22. Preferably, the lower orterminal portion of the upright joints 34 is brought into intersecting,united relationship with the outermost ringlike expansion joint 36 inthe bottom 20. The intersection between the upright joints 34 and theoutermost joint 36 provides a far simpler construction than structuresused in the prior art, which involve using three dimensional expansionjoints for avoiding excessive stresses at the intersection of a verticalliner section with the floor liner section. The intersection between theupright expansion joint 34 and the floor joint 36 is accomplished by aV-shaped inte rsection between these joints 34. As shown clearly inF105. 3' and 5, the planar sections 32 are joined to the uprightexpansion joint section 34 by suitable means, as by welding at the joint38. A plurality of metal sheet sections may be welded or joined togetherby other suitable means to form the planar sections 32 in a mannersimilar to that used for forming the central portion 28 of the bottom 20of the liner 18. The upright expansion joints 34 compensate forcircumferential expansion and contraction of the sides of the liner 22.

The resiliently mounted support member 26 is desirably a ringlikestructure which is rigidly joined at a plurality of spaced locations toupright rods or tubes 40. The hanger members 42 are mounted on the uppersurface of the roof 14 of the tank 10. The hangers 42 are located indirect alignment above the support member 26. The support member 26 isconstructed so as to be in close proximity to the walls 12 of the tank10 and so as to provide assurance that the sides 22 of the liner 18remain substantially coextensive with the tank walls 12 at all times.

The hanger members 42 each include a flange portion 44 which is rigidlysecured on the upper surface of the roof 14. An outer tubular member 46is threadably secured to the threaded portion of the flange 44 andextends upwardly therefrom. The upper end of the tube 46 is closed by acap 48 which is threadably secured to the upper end of the tube 46. Thetubular member 46 defines a housing for a compression spring 50 which islocated in the annular space between an upright rod or tube 40 and theouter tube 46. A collar 52 is removably secured to the upper end of theupright tube 40 by means of a pin 54. The upper end of the compressionspring 50 engages the collar 52 and the lower end of the compressionspring 50 engages the upper end of the flange 44.

The hanger members 42 thereby provide resilient support for the supportmember 26 and thereby for the liner 18. The weight of the liner 18 andthe weight of the liquid contained within the liner 18 cause downwardmovement of the support member 26. This downward movement compresses thespring 50 because the spring 50 is trapped between the collar 52 and theflange 44. The compression springs 50 provide resilient mounting of theliner 18 and thus compensate for vertical expansion and contraction ofthe sides 22 to accommodate for height variation depending upon thedepth of the liquid contained within the liner 18, without creating anysignificant stresses in the liner material which could ultimately causebreaks to form therein. Preferably a packing gland 56 is interposedbetween the flange 44 and the outer surface of the upright tube 40 so asto prevent gas leakage from the tank storage area.

The compression spring 50 is designed so as to allow for the contractionof the liner material. Thus, with the proper spring constant, when thewall material cools and contracts or heats and expands, excessivestresses will not be set up in the material which can ultimately lead tofailure of the liner. The compression spring has a load due to theweight of the liner material itself and due to the weight of the liquidcontained therein, and it also has a load due to the contraction of thewall material. The spring constant is chosen so that the force requiredto compress the spring an amount necessary to allow for the contractionof the wall material is only a relatively small percentage of theproportional stress limit of the material. Since the loading due tocontraction is only a small percentage of the loading due to thematerial weight, the compression spring is relatively long. In order tokeep the length of the total assembly within reasonable limits, it isdesirable to precompress the spring to about 90-95 percent of thematerial weight load before it is installed.

Referring now to the embodiment of FIGS. 7- 10, the tank 70 showntherein is located entirely below the ground so that the upwardlyprojecting hanger members 42 of the embodiment of FIGS. l-6 cannot beused. The essential differences between the embodiment of FIGS. 1-6 andthe embodiment of FIGS. 7-10 lie in the construction of the hangermembers, although it is to be understood that the principle of bothliner systems is substantially the same. The construction of the liner72 in the tank 70 is substantially the same as liner 18 for the tank 10.The only difference between the embodiment of FIGS. 7-10 and of FIGS.1-6 is that the liner 72 uses a different type of strap member 74 forengaging the ringlike support 76, which is resiliently mounted from aplurality of hanger members 78. It is noted that each strap 74 iselongated and constitutes a continuation of the liner material which isfolded upon itself and welded in place over the ringlike support 76.

A peripheral beam 80 is rigidly secured to the underside of the roof 82of the tank 70 by use of bolts 84. The underside of the peripheralringlike beam 80 has a plurality of downwardly extending tubes or rods86 projecting therefrom. These tubes are equally spaced at a pluralityof locations therearound. The lower end of the tube 86 includes abearing plate 88 which is rigidly secured thereto by suitable means, asby welding. An outer tubular member or housing 90 is slidably mountedaround the downwardly extending tube 86. An upper bearing plate 92 isthreadably secured to the upper end of the tubular housing 90. Acompression spring 94 is interposed between the bearing plate 92 and thebearing plate 88 and is contained within the annular space between thetubular member 86 and the outer housing 90.

The lower end of the tubular housing 90 is rigidly secured, as bywelding, to the ringlike support member 76 around which the strapmembers 74 are passed to provide support for the liner 72. It is thusseen that the compression springs 94 provide for the same type ofsupport for the liner 72 as is provided by the compression springs 50for the liner 18. As the liquid depth is varied within the liner 72,less load is applied to the resiliently mounted support 76 and thecompression springs 94 tend to lift the support 76 upwardly through theouter housing 90 and the bearing plate 92. The hanger members 78 thuscompensate for vertical expansion and contraction of the sides of theliner 72.

It is seen from the foregoing description that we have provided a linersystem of relatively simple construction which compensates for expansionand contraction thereof due to great variations in temperature. Theconstruction provides for expansion joints in the floor for radialexpansion and contraction. Both the embodiments also provide forcircumferential expansion and contraction of the sides, and provide forvertica expansion and contraction of the sides. II this is accomplishedin a relatively simple, but highly effective manner. The same basicprinciples are used in the support of the liner regardless of whetherthe tank structure is contained entirely above the ground or partiallyabove the ground and partially below the ground. The only variation isin the specific design of the hanger members which are supported by theroof of the tank for the purpose of vertically supporting the linersides in a resilient manner.

We claim:

I. A system for retaining liquid in a storage tank structure, saidsystem comprising a storage tank having an upper portion, sidewalls, anda floor, continuous liner means having sides substantially coextensivewith said sidewalls and having a bottom substantially coextensive withsaid floor, upright expansion joint sections integrally joined to saidsides of said liner means compensating for circumferential expansion andcontraction of said sides, ringlike expansion joint sections integrallyjoined to said bottom of said liner means compensating for expansion andcontraction of said bottom, hanger members resiliently secured to saidupper portion of said tank structure, and means secured to the upper endportions of said sides of said liner means for engaging said hangermembers whereby said sides are suspended in a position substantiallycoextensive with said sidewalls and said bottom is maintained in aposition substantially coextensive with said floor.

2. The system of claim 1 wherein said upright expansion joint sectionsin said sides extend to intersect said ringlike expansion joint sectionsin said bottom so as to allow for movement of said liner means in alldirections at the intersection between said side and said bottom.

3. The system of claim 1 wherein the upper portion of said storage tankis above the ground and said hanger members extend outwardly above saidupper portion.

4. The system of claim 1 wherein the upper portion of said storage tankstructure is below the ground and the said hanger members are enclosedwithin said storage tanks and extend downwardly from said upper portion.

5. The system of claim 1 wherein said hanger members include springmeans for resiliently supporting said sides in a vertical direction tocompensate for vertical expansion and contraction of said sides of saidliner means.

6. The system of claim 5 wherein said upright expansion joint sectionsand said ringlike expansion joint sections intersect so as to compensatefor expansion and contraction in all directions at the intersection ofsaid side and said bottom, thereby avoiding excessive stresses in saidbottom of said liner means.

7. The system of claim 1 wherein said liner means is a flexible metallicmaterial, said expansion joint means generally comprising corrugatedsections.

8. The system of claim 1 wherein the said liner means comprise aplurality of planar substantially flexible metallic material sectionswelded together in a desired configuration so as to provide continuousliner means, and said expansion joint sections comprises unitarycorrugated metallic members,

united to the planar portions of said liner means.

9. The system of claim 1 wherein said first expansion joint sectionscomprise substantially upright metallic corrugations, said secondexpansion joint sections integrally joined to said bottom of said linermeans, said upright corrugations extend into said ringlike sections, andthe outermost of said ringlike portions intersect the said extendingportions of said upright corrugations in said sides.

10. The system of claim 1 wherein said hanger members comprise supportmembers resiliently mounted in a vertical direction to compensate forexpansion and contraction of said sides in a vertical direction.

1. A system for retaining liquid in a storage tank structure, saidsystem comprising a storage tank having an upper portion, sidewalls, anda floor, continuous liner means having sides substantially coextensivewith said sidewalls and having a bottom substantially coextensive withsaid floor, upright expansion joint sections integrally joined to saidsides of said liner means compensating for circumferential expansion andcontraction of said sides, ringlike expansion joint sections integrallyjoined to said bottom of said liner means compensating for expansion andcontraction of said bottom, hanger members resiliently secured to saidupper portion of said tank structure, and means secured to the upper endportions of said sides of said liner means for engaging said hangermembers whereby said sides are suspended in a position substantiallycoextensive with said sidewalls and said bottom is maintained in aposition substantially coexteNsive with said floor.
 2. The system ofclaim 1 wherein said upright expansion joint sections in said sidesextend to intersect said ringlike expansion joint sections in saidbottom so as to allow for movement of said liner means in all directionsat the intersection between said side and said bottom.
 3. The system ofclaim 1 wherein the upper portion of said storage tank is above theground and said hanger members extend outwardly above said upperportion.
 4. The system of claim 1 wherein the upper portion of saidstorage tank structure is below the ground and the said hanger membersare enclosed within said storage tanks and extend downwardly from saidupper portion.
 5. The system of claim 1 wherein said hanger membersinclude spring means for resiliently supporting said sides in a verticaldirection to compensate for vertical expansion and contraction of saidsides of said liner means.
 6. The system of claim 5 wherein said uprightexpansion joint sections and said ringlike expansion joint sectionsintersect so as to compensate for expansion and contraction in alldirections at the intersection of said side and said bottom, therebyavoiding excessive stresses in said bottom of said liner means.
 7. Thesystem of claim 1 wherein said liner means is a flexible metallicmaterial, said expansion joint means generally comprising corrugatedsections.
 8. The system of claim 1 wherein the said liner means comprisea plurality of planar substantially flexible metallic material sectionswelded together in a desired configuration so as to provide continuousliner means, and said expansion joint sections comprises unitarycorrugated metallic members united to the planar portions of said linermeans.
 9. The system of claim 1 wherein said first expansion jointsections comprise substantially upright metallic corrugations, saidsecond expansion joint sections integrally joined to said bottom of saidliner means, said upright corrugations extend into said ringlikesections, and the outermost of said ringlike portions intersect the saidextending portions of said upright corrugations in said sides.
 10. Thesystem of claim 1 wherein said hanger members comprise support membersresiliently mounted in a vertical direction to compensate for expansionand contraction of said sides in a vertical direction.